///
// * jdbm LICENSE v1.00
// *
// * Redistribution and use of this software and associated documentation
// * ("Software"), with or without modification, are permitted provided
// * that the following conditions are met:
// *
// * 1. Redistributions of source code must retain copyright
// *    statements and notices.  Redistributions must also contain a
// *    copy of this document.
// *
// * 2. Redistributions in binary form must reproduce the
// *    above copyright notice, this list of conditions and the
// *    following disclaimer in the documentation and/or other
// *    materials provided with the distribution.
// *
// * 3. The name "jdbm" must not be used to endorse or promote
// *    products derived from this Software without prior written
// *    permission of Cees de Groot.  For written permission,
// *    please contact cg@cdegroot.com.
// *
// * 4. Products derived from this Software may not be called "jdbm"
// *    nor may "jdbm" appear in their names without prior written
// *    permission of Cees de Groot.
// *
// * 5. Due credit should be given to the jdbm Project
// *    (http://jdbm.sourceforge.net/).
// *
// * THIS SOFTWARE IS PROVIDED BY THE ndbm PROJECT AND CONTRIBUTORS
// * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
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// * CEES DE GROOT OR ANY CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
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// * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
// * OF THE POSSIBILITY OF SUCH DAMAGE.
// *
// * Copyright 2000 (C) Cees de Groot. All Rights Reserved.
// * Contributions are Copyright (C) 2000 by their associated contributors.
// *
// * $Id: CachePolicy.java,v 1.5 2003/11/01 13:25:02 dranatunga Exp $
// 

//*************************************************************************
//**  Included in JDMB 1.0 port to SharpDBM;  11/2013 Cyrus Neah cneah@codingreal.com
//**  SharpDBM is an independent reimplementation of the JDBM 1.0 software library in C#  
//*************************************************************************

using System;
using System.Collections;

namespace SharpDBM.helper
{


///
// *  CachePolicity is an abstraction for different cache policies.
// *  (ie. MRU, time-based, soft-refs, ...)
// *
// * @author <a href="mailto:boisvert@intalio.com">Alex Boisvert</a>
// * @author <a href="mailto:dranatunga@users.sourceforge.net">Dilum Ranatunga</a>
// * @version $Id: CachePolicy.java,v 1.5 2003/11/01 13:25:02 dranatunga Exp $
// 
	public interface CachePolicy
	{

//    *
//     * Place an object in the cache. If the cache does not currently contain
//     * an object for the key specified, this mapping is added. If an object
//     * currently exists under the specified key, the current object is
//     * replaced with the new object.
//     * <p>
//     * If the changes to the cache cause the eviction of any objects
//     * <strong>stored under other key(s)</strong>, events corresponding to
//     * the evictions are fired for each object. If an event listener is
//     * unable to handle the eviction, and throws a cache eviction exception,
//     * that exception is propagated to the caller. If such an exception is
//     * thrown, the cache itself should be left as it was before the
//     * <code>put()</code> operation was invoked: the the object whose
//     * eviction failed is still in the cache, and the new insertion or
//     * modification is reverted.
//     *
//     * @param key key for the cached object
//     * @param value the cached object
//     * @throws CacheEvictionException propagated if, while evicting objects
//     *     to make room for new object, an eviction listener encountered
//     *     this problem.
//     
		void put(object key, object value);
 
//			throws CacheEvictionException;


//    *
//     * Obtain the object stored under the key specified.
//     *
//     * @param key key the object was cached under
//     * @return the object if it is still in the cache, null otherwise.
//     
		object @get(object key);


//    *
//     * Remove the object stored under the key specified. Note that since
//     * eviction notices are only fired when objects under <strong>different
//     * keys</strong> are evicted, no event is fired for any object stored
//     * under this key (see {@link #put(Object, Object) put( )}).
//     *
//     * @param key key the object was stored in the cache under.
//     
		void remove(object key);


//    *
//     * Remove all objects from the cache. Consistent with
//     * {@link #remove(Object) remove( )}, no eviction notices are fired.
//     
		void removeAll();


//    *
//     * Enumerate through the objects currently in the cache.
//     
		IEnumerator elements();


//    *
//     * Add a listener to this cache policy.
//     * <p>
//     * If this cache policy already contains a listener that is equal to
//     * the one being added, this call has no effect.
//     *
//     * @param listener the (non-null) listener to add to this policy
//     * @throws ArgumentOutOfRangeException if listener is null.
//     
		void addListener(CachePolicyListener listener);
 
//				throws ArgumentOutOfRangeException;


//    *
//     * Remove a listener from this cache policy. The listener is found
//     * using object equality, not identity.
//     *
//     * @param listener the listener to remove from this policy
//     
		void removeListener(CachePolicyListener listener);

	}

}